This disclosure is generally directed to curable gel inks, such as radiation-curable phase-change inks, and their use in forming images, such as through inkjet printing. More specifically, this disclosure is directed to radiation-curable gel inks, such as ultraviolet-light-curable phase-change inks, that comprise a curable gellant and a curable solid.
Inkjet printing systems are known in the art, and thus extensive description of such devices is not required herein. Phase change or “hot melt” inks are desirable for ink jet printers because they remain in a solid phase at room temperature during shipping, long term storage, and the like. In addition, the problems associated with nozzle clogging as a result of ink evaporation with liquid ink jet inks are largely eliminated, thereby improving the reliability of the ink jet printing. Further, in phase change ink jet printers wherein the ink droplets are applied directly onto the final recording substrate (for example, paper, plastic, cardboard, and the like), the droplets solidify immediately upon contact with the substrate, so that migration of ink along the printing medium is prevented and dot quality is improved.
While known phase change ink compositions are used successfully, a need remains for improved phase-change ink compositions that do not exhibit, or exhibit reduced, separation of an ink liquid component after a drop of ink contacts the substrate. This phenomenon is known as syneresis, which results in (1) increased showthrough of the ink on the substrate, (2) undesirable halos around printed ink drops and (3) increased difficulty in spreading and leveling. Such ink compositions would also be processed at lower temperatures and with lower energy consumption, and would have improved jetting reliability and latitude with respect to meeting the jetting and transfuse requirements of curable ink compositions.
The present disclosure, in embodiments, addresses one or more of these needs by providing a radiation curable phase change ink composition containing at least one curable solid and at least one gellant, and the use of such inks in methods for forming images, particularly their use in inkjet printing.